I'm including the old markup. It Needs More Examples!
(just when those itchy tropers who cannot launch correctly but try anyway will stop...)
Okay, I'm rewriting this trope to fit the requirements for a good article.
In Real Life, a metal is an element of the periodic table which belongs to one of certain groups/columns and has a specific type crystal lattice with free electrons. In fiction, especially fantasy, a metal is shiny stuff with wonderful properties like super strength, lightness, magic resistance and so on, often not resembling any of the metals found in the periodic table. Metals that are brittle, soft, flammable, react violently with water or air or are otherwise useless for smithing swords and shields from them never appear in fantasy, despite there being a lot of these in Real Life. This trope (a supertrope to Mithril and Orichalcum) describes the "shiny and wondrous" kind of metals.
Note that this is mostly a Fantasy trope. Science-fiction examples are only good if they are from a work that is "science" in name only (such as four-color comics or space fantasy like Star Wars or Warhammer 40,000); harder-science materials actually explained as high-tech alloys with some verisimilitude aren't. In a nutshell, Wolverine's adamantium and Boba Fett's Mandalorian iron are examples of this trope, but a composite alloy of titanium and carbon nanotubes isn't.
Real Life examples are only allowed if they are in fact occult superstitions (like hard mercury) or well-known hoaxes (like red mercury).
The most often-encountered types of fantasy metal are:
Mithril (variously spelled mithral, mythral or mythril): a lightweight, very strong, silvery metal, similar to the real-world metal titanium. The name is Sindarin for "silvery glitter". Appeared in J.R.R.Tolkien's Lord of the Rings as an Infinity Plus One Metal, but in later examples it's a mid-level miracle metal only, above steel but below adamantium.
Orichalcum (variously spelled orichalcon, orihalcon or orichalc): a metal first appeared in Plato's version of the Atlantis myth. The name means "mountain copper" in Greek, and it, indeed, often appears the color of copper or bronze. Orihalcum's properties vary heavily from source to source: sometimes its schtick is strength, sometimes it's high value, sometimes it's magic resistance, sometimes it's room-temperature superconductivity.
Adamantium (variously spelled adamantine, adamantite or adamant): this troper is unsure where it first appeared, probably also in Greek myths, but the name comes from Greek "adamas", that means diamond. And, indeed, this metal is diamond-hard and much more strong and resilient than diamond to boot.
Meteoric iron (variously called sky iron, Thunderbolt Iron, star iron, and so on) is a real alloy, but its depiction in fantasy is very often a very different metal than it is in reality. The typical "miraculous" meteoric iron is a jet-black metal that is much stronger than regular iron and often has magical properties as well.
The list of fantasy metals is much more than that, but most examples are work-specific and shall be listed in the examples list.
A fantasy-specific subtrope (or, maybe, sister trope?) of Unobtainium.
J. R. R. Tolkien's Arda has, beyond mithril, a jet-black metal called galvorn. Galvorn, even stronger than mithril, is invented by Eol the Dark Elf and the secret of its making was lost when he and his son Maeglin, who also had the know-how, died.
The Book of Lost Tales, Tolkien's very early draft for Silmarillion, also gives us tilkal, an Infinity Plus One Metal that can only be made by Aule, the god of blacksmiths. Its name is an acronym of Quenya names for iron, copper, silver, gold, tin and lead, the six naturally occurring metals known to the Elves, used as its ingredients.
TES' Mithril is a lightweight, mid-level metal used to make armor. It's otherwise typical and fairly unremarkable.
Ebony is a dark gray or brownish-gray metal, sometimes with brown or yellowish veinlets, that is very heavy and very strong, used to make superb weapons and armor.
Daedric metal is a special kind of Ebony which is infused with demonic souls. It's dark gray with red veinlets, and, basically, Ebony But More So. It's always the high-end, top of the line metal in the games.
Elven Steel is a kind of superb steel with greenish or golden hue. In Skyrim, its recipe was revealed: it's made by treating iron with a mineral called moonstone; the weapons variant of the steel has also some quicksilver (mercury?) added.
Orcish Steel was always assumed to be just high-quality steel, but in Skyrim it was revealed (or retconned?) that it's an alloy of iron and orihalcon.
Dwarven Metal is a Lost Technology alloy that looks like copper or bronze, but its exact composition (and even its proper Dwemer name) is forgotten.
Adamantium is a rare metal in this 'verse, not appearing in all games; in Morrowind it's a high grade, silvery metal for weapons and armor, almost on par with ebony. It's the best metal for making medium armor; technically, Indoril armor is better, but it's bonemold rather than metallic and it's impractical to wear it because it angers Ordinators.
"Glass" isn't a metal, but is treated here as metal-like. It's supposedly some kind of super strong, lightweight and resilient volcanic glass that is green. In Morrowind, natural glass was mined; in Skyrim, Morrowind's mines were out of order because of a slight local apocalypse, so glass was smelted artificially by melting moonstone and malachite together.
The Elder Scrolls also has Skyforge Steel (technically just steel forged using a special process, but otherwise fits due to the results).
In real-world occult alchemy, there was believed that a method exists to make mercury hard at room temperature. At least one medieval Hermetic recipe exists to make a ring of invisibility from hard mercury.
Red mercury was a hoax perpetrated by Soviet KGB. It was ascribed some miraculous properties like making simple and compact nukes; the purpose of the hoax was sting operations to catch terrorists and rogue state agents seeking easy ways to obtain nukes.
Cortosis, which is a metal hostile to the Force and also with an ability to short out lightsabers. Another famous ability of cortosis is that its ores are constantly electrified and capable of electrocuting anyone who handles them carelessly.
Phrik is similar to cortosis, but more tame. It doesn't short out lightsabers, but is immune to them as well.
Beskar (Mandalorian iron) is similar to phrik. Mandalorian armors are typically made of beskar.
Many artifacts of the Mi-Go, Yith, and other Starfish Aliens from H.P. Lovecraft's works were crafted from metals unknown to human metallurgy. (More scifi/horror than fantasy, but could still be worth a mention.)
The core rulebooks of Dungeons & Dragons have adamantine, mithral, cold iron (effective against fey), and alchemical silver (silver alchemically bonded to steel for use against lycanthropes). Secondary materials include other metals such as starmetal.
The Eberron campaign setting introduces byeshk (heavy purple metal useful against abominations), flametouched iron (good-aligned), and Riedran crysteel (psionically charged crystal bonded to iron).
First, second, and third edition D&D drow had their own alloy of adamantine (or mithral, depending on the writer) that gave bonuses to arms and armor, but was instantly rendered brittle and useless by exposure to sunlight.
A list of magical metals on a website. Includes Steel (Dark, Abyssimal Red, Baatorian Green and Forest}, Mithril (Black, White, Silver and Githank), Adamantium, Celestium, Dwarven Blackrock, Illithium, Mechanium, Neutralite and Temporal Silver.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.